Aspiration requirements for the transportation of retrievably stored waste in the TRUPACT-2 package

The Transuranic Package Transporter-II (TRUPACT-II) is the shipping package to be used for the transportation of contact-handled transuranic (CH TRU) waste between the various US Department of Energy (DOE) sites, and to the Waste Isolation Pilot Plant (WIPP) located near Carlsbad, New Mexico. Waste (payload) containers to be transported in the TRUPACT-II package are required to be vented prior to being shipped. ''Venting'' refers to the installation of one or more carbon composite filters in the lid of the container, and the puncturing of a rigid liner (if present). This ensures that there is no buildup of pressure or potentially flammable gas concentrations in the container prior to transport. Payload containers in retrievable storage that have been stored in an unvented condition at the DOE sites, may have generated and accumulated potentially flammable concentrations of gases (primarily due to generation of hydrogen by radiolysis) during the unvented storage period. Such payload containers need to be aspirated for a sufficient period of time until safe pre-transport conditions (acceptably low hydrogen concentrations) are achieved. The period of time for which a payload container needs to be in a vented condition before qualifying for transport in a TRUPACT-II package is defined as the ''aspiration time.'' This paper presents the basis for evaluating the minimum aspiration time for a payload container that has been in unvented storage. Three different options available to the DOE sites for meeting the aspiration requirements are described in this paper. 4 refs., 2 figs